This invention relates to a cooling device for a rotary electric machine, and more particularly to the ventilation of a stator coil end portion.
A prior-art cooling device for a rotary electric machine of the pertinent type has been as shown in FIG. 1. Referring to the figure, numeral 1 designates a frame which has a plurality of side plates 1a, numeral 2 a stator core, numerals 3 and 4 ventilating ducts of the stator core, and numeral 5 a stator clamper which serves to hold the stator core 2 in a sandwiched fashion and in which a plurality of ventilating holes 5a are provided at equal intervals in the circumferential direction thereof. Numeral 6 indicates that end portion of a stator coil which protrudes from the stator core 2, and numeral 7 a ventilation guide which covers the stator coil end portion 6 and which is constructed of a shroud 8 and a wind receiver 9 to be described next. The shroud 8 is mounted on the stator clamper 5, while the wind receiver 9 is fixed to the shroud 8 by bolts. Numeral 10 indicates a breath ring which is mounted on the stator coil end portion 6, numeral 11 a supporting arm which holds the breath ring 10 on the stator clamper 5, numeral 12 a bracket cover which is detachably mounted on an axial end part of the frame 1, numeral 13 a rotary shaft, numeral 14 a rotor core, numeral 15 a ventilating duct of the rotor core, numeral 16 an axial fan, numeral 17 an air inlet which is opened in the upper part of the frame 1, numeral 18 an air outlet which is opened in the upper part of the frame 1 over the stator core 2, and numeral 19 an air intake passage which is formed between the ventilation guide 7 and the bracket cover 12. Letters A denote spacers which are interposed between top coils or bottom coils in the stator coil end portion 6, while letter B denotes a connecting lead for, e. g., the poles of the stator coil.
The supporting arm 11 is mounted on the stator clamper 5, and the end portion 6 of the stator coil is supported by the breath ring 10 fixed to the supporting arm 11. The frame 1 is open on the side over the shroud 8 and the side over the stator core 2, and the open sides form the air inlet 17 and the air outlet 18 respectively.
Cooling air drawn by suction through the air inlet 17 by means of the axial fan 16 passes via the air intake passage 19 outside the ventilation guide 7 and then centrifugally through the interspaces between the wind receiver 9 and the stator coil end portion 6 and between the coils of the stator coil end portion 6, as indicated by arrows. Further, it is sent on to the outer peripheral side of the stator core 2 through the ventilating holes 5a of the stator clamper 5 and the ventilating duct 4 at the end part of the stator core 2, whereupon it is emitted from the air outlet 18. In addition, part of the cooling air drawn by suction passes from the inner periphery of the rotor core 14 via the ventilating ducts 15, 3 of the cores to the outer periphery of the stator core 2, from which it is emitted to the exterior.
Since the prior-art rotary electric machine is constructed as described above, the interspace between the coils of the stator coil end portion is narrow whereas the wind receiver and the stator coil end portion are widely spaced. Therefore, the greater part of the cooling air passes through the interspace between the wind receiver and the stator coil end portion, and a sufficient quantity of ventilation cannot be secured through the interspace between the coils, so that the cooling of the stator coils is not performed effectively.